Texas A&M University oceanography professor John Kessler, just back from a 10-day research expedition near the BP Plc oil spill in the gulf, says methane gas levels in some areas are "astonishingly high."

Kessler's crew took measurements of both surface and deep water within a 5-mile (8 kilometer) radius of BP's broken wellhead.

"There is an incredible amount of methane in there," Kessler told reporters in a telephone briefing.

In some areas, the crew of 12 scientists found concentrations that were 100,000 times higher than normal.